6502/65C02 emulator written in standard C99 with no external dependencies.
Initially created for my HBC-56 (6502 on a backplane) Emulator
Includes:
- Support for standard 6502/6510, 65C02, WDC65C02 and R65C02.
- Supports all unofficial ("illegal") 6502/6510 opcodes (Use model value
CPU_6502U). - Correct handling of Decimal mode.
- Accurate instruction timing.
- All WDC and Rockwell-specific 65C02 instructions.
- User-supplied I/O callbacks.
- IRQ and NMI signals.
- Multiple CPU instances.
- Instruction disassembler.
- Test runner.
Includes a test program which was designed to run Klaus Dormann's 6502 tests.
Passes all tests:
- 6502_functional_test (all models)
- 6502_decimal_test (with valid and invalid bcd) (6502)
- 65C02_decimal_test (with valid and invalid bcd) (all 65C02 models)
- 65C02_extended_opcodes_test (Standard 65C02)
- W65C02_extended_opcodes_test (WDC65C02)
- R65C02_extended_opcodes_test (R65C02)
See the test directory or more details.
vrEmu6502 uses the CMake build system
git clone https://github.com/visrealm/vrEmu6502.git
cd vrEmu6502
mkdir build
cd build
cmake ..
cmake --build .
Windows: Optionally, open the generated solution file
ctest
Windows: Optionally, build the ALL_TESTS project in the generated solution file
#include "vrEmu6502.h"
uint8_t ram[0x8000];
uint8_t rom[0x8000];
uint8_t My6502MemoryReadFunction(uint16_t addr, bool isDbg)
{
if (addr < 0x8000)
{
return ram[addr];
}
return rom[addr & 0x7fff];
}
void My6502MemoryWriteFunction(uint16_t addr, uint8_t val)
{
if (addr < 0x8000)
{
ram[addr] = val;
}
}
/* fill rom with something that makes sense here */
/* create a new WDC 65C02. */
VrEmu6502 *my6502 = vrEmu6502New(CPU_W65C02, My6502MemoryReadFunction, My6502MemoryWriteFunction);
if (my6502)
{
/* if you want to interrupt the CPU, get a handle to its IRQ "pin" */
vrEmu6502Interrupt *irq = vrEmu6502Int(my6502);
/* reset the cpu (technically don't need to do this as vrEmu6502New does reset it) */
vrEmu6502Reset(my6502);
while (1)
{
/* call me once for each clock cycle (eg. 1,000,000 times per second for a 1MHz clock) */
vrEmu6502Tick(my6502);
/* interrupt it? */
if (myHardwareWantsAttention)
{
*irq = IntRequested;
/* at some point, the hardware will be happy and it will need to release the interrupt */
}
}
vrEmu6502Destroy(my6502);
my6502 = NULL;
}See HBC-56 for real-life example usage.
This code is licensed under the MIT license